1. Field of the Invention
The present invention relates to an imaging system which improves the quality of image data obtained by imaging an optical image of a subject using restoration processing, an imaging apparatus having the imaging system, a portable terminal apparatus having the imaging system, an onboard apparatus having the imaging system, and a medical apparatus having the imaging system.
2. Description of Related Art
An imaging system that forms an optical image of a subject, which is focused on a light receiving surface through an imaging lens, by utilizing an imaging device, such as a CCD or a CMOS device, having the light receiving surface on which a plurality of light receiving pixels are two-dimensionally arrayed is known.
As an example of such an imaging system, an onboard camera or a portable cellular phone camera in which an imaging system having an imaging lens designed such that the depth of field increases is attached directly on a circuit board is known (refer to JP-A-2007-147951). Such an imaging system directly attached to a circuit board is designed to have a small device size since the size is limited.
In addition, among imaging system mounted in onboard cameras or portable cellular phone cameras with high performance, one in which the resolving power of an imaging lens is close to a diffraction limited is also known.
On the other hand, it has been requested to further improve the resolution for an image obtained by using such an imaging system.
In order to improve the resolution of an image obtained by an imaging system, it is necessary to increase the number of light receiving pixels and increase the resolving power of an imaging lens. That is, for example, by increasing the pixel density of light receiving pixels arrayed on a light receiving surface of an imaging device and increasing the resolving power of an imaging lens such that a point image projected onto the light receiving surface through the imaging lens falls within a range of one light receiving pixel, the resolution of the image obtained by using the imaging system can be improved.
Here, increasing the pixel density of light receiving pixels that form the imaging device without making the device size large may be realized relatively easily by an improvement in a technique in recent years.
On the other hand, it is very difficult to improve the resolving power of an imaging lens. That is, in order to make the size of the imaging lens large or improve the resolution of the imaging lens without making a depth of field small, it is necessary to suppress a shape error, an assembly error, and the like of each lens that forms the imaging lens. However, since there is an imaging lens the resolving power of which is already increased up to a level close to the diffraction limited, there is a problem that it is very difficult to increase the resolving power by further improving manufacturing accuracy (for example, machining accuracy, assembly accuracy, and adjustment accuracy).